In conventional technology, there is known a gusset bag provided with a spout as a gusset-type bag formed of a film material such as polyester in which a spout is attached to an upper edge portion of the gusset-type bag. Patent Document 1 (Japanese Patent Laid-open Publication No. 2002-179102), as one example of such gusset-type bag, discloses a following gusset bag with a spout. Hereunder, this gusset bag provided with the spout is referred to as a conventional gusset bag A, which will be explained with reference to the accompanying drawing.
FIG. 10 is a perspective view illustrating a conventional gusset bag A.
As shown in FIG. 10, the conventional gusset bag A is composed of a bag body 11 and a spout 12 provided with a cap 3. The spout 12 is attached to the upper edge portion of the bag body 11 so as to allow an interior of the bag body 11 to communicate with an exterior of thereof.
The bag body 11 is formed from a pair of opposing flat surface portions 14, a pair of side surface portions 15 having side edge portions heat-sealed to side edge portions of the respective flat surface portions 14 so as to have a side surface gusset forming foldable lines (L1), and a bottom surface portion 16 formed to a lower edge portion of the bag body 11. The bottom surface portion 16 is formed in a manner in which lower portions of the paired flat surface portions, to which the side surface portions 15 are sealed, are folded inward each by a predetermined length.
The conventional gusset bag A, however, provides the following defects.
In a case when much inner content remains in the bag body 11, the bottom surface portion 16 can maintain a flatness to some extent because of self-weight of the inner content and ensure its self-standing performance, but when the amount of the remaining inner content reduces, it becomes difficult to maintain inwardly folded condition of the lower portions of the paired flat surface portions 14. As a result, it becomes impossible for the bottom surface portion to maintain its flatness and hence difficult to ensure the stable self-standing ability.
When the remaining amount of the inner content reduces, if the self-standing performance is not ensured, the following problem will be caused.
For example, the conventional gusset bag A is used as a soy-source bag, which is repeatedly used, the bog body 11 is liable to fall over according to reducing of the remaining amount of the soy-source and difficult to be used as soy-source bag, and in a certain case, there may cause a feat that the bag body 11 itself falls over and the soy-source flows outward.
Then, a gusset bag provided with a spout that solved the problem encountered in the conventional gusset bag A mentioned above has been proposed as one example that is disclosed in Patent Document 2 (Japanese Patent Laid-open Publication No. 2008-44641). Hereunder, this gusset bag is referred to as conventional gusset bag B, which will be explained with reference to the accompanying drawing.
FIG. 11 is a perspective view illustrating the conventional gusset bag B.
As shown in FIG. 11, the conventional gusset bag B is composed of a bag body 21 and a spout 22 provided with a cap 27. The spout 22 is attached to the central position of the upper edge portion of the bag body 21 so as to allow an interior of the bag body 21 to communicate with an exterior thereof.
The bag body 21 is formed from a tubular body portion 23 and a bottom surface portion 24 heat-sealed to a lower edge portion of the tubular body portion 23. The tubular body portion 23 is composed of a pair of opposing flat surface portions 25 and a pair of side surface portions 26 heat-sealed to the side edge portions of the paired flat surface portions 25. The side surface portions 26 are formed with foldable lines (L2), respectively, for forming side surface gussets.
The bottom surface portion 24 has entire peripheral edge portion (margin) to be heat-sealed and secured to the flat surface portions 25 forming the tubular body portion 23 and the inner surface of the lower edge portions (margins) of the side surface portions 26. The bottom portion 24 is folded into a boat-shape to thereby form a bottom surface gusset of the bag body 21 (see FIG. 6).
According to the conventional gusset bag B, by heat-sealing the bottom surface portion 24 to the lower edge portion of the tubular body portion 23, the bottom surface portion 24 can always maintain its flatness and hence ensure self-standing attitude regardless of remaining amount of the inner content.
The conventional gusset bag B, however, provides the following defects.
When it is required to pour out the inner content, the bag body 21 is inclined. However, if the remaining amount of the inner content is reduced, it is difficult to pour out the inner content as long as the bag body 21 is largely inclined because the spout 22 is attached to the central portion of the upper edge portion of the bog body 21, and accordingly, there is a fear that some amount of the inner content remains inside the bag body 21.
The above defect may be solved to some extent by attaching the spout 22 to a corner portion of the bag body 21.
Then, a gusset bag provided with a spout in which the spout is attached to the corner portion of the bag body is disclosed in Patent Document 3 (Japanese Design Patent Registration No. 584889). Hereunder, this gusset bag provided with the spout disclosed in this Document 3 is referred to as conventional gusset bag C, which will be explained with reference to the accompanying drawing.
FIG. 12 is a perspective view showing the conventional gusset bag C.
As shown in FIG. 12, the conventional gusset bag C is composed of a bag body 41 formed with a pair of flat surface portions 42 and a spout 43, provided with a cap 44, attached to one of upper corner portions of the bag body 41.
In the conventional gusset bag C, since the spout 43 is attached to the upper corner portion of the bag body 41, the inner content is easily taken out, but since any gusset is not formed to the side portion of the bag body 41, the self-standing ability of the bag body 41 becomes worse when the remaining amount of the inner content is reduced, thus being inconvenient.
Furthermore, another-type of a gusset bag provided with a spout to a corner portion of a bog body is disclosed in Patent Document 4 (Japanese Patent Laid-open Publication No. HEI 11-292105), and hereunder, this gusset bag will be referred to as a conventional gusset bag D and explained with reference to the drawings.
FIG. 13 is a perspective view of the conventional gusset bag D.
As shown in FIG. 13, the conventional gusset bag D is composed of a bag body 53 which has a longitudinally long length and has both end portions each of which has a sealed head-like shape of a milk carton, and a spout 54 provided with a cap 55 attached to either one end seal portion of the bag body 53.
According to the structure of the above conventional gusset bag D, the inner content can be easily taken out and the gusset bag D has an excellent self-standing performance. On the other hand, it is difficult to stock the bag D because of its wide width, and moreover, since the spout 54 is attached to the end seal portion of the bag body 53, it is difficult to completely pour out the inner content even if the bag body 53 is inclined and some amount of inner content remains inside the bag body 53, thus being inconvenient.